Tasked with determining whether police were using racial profiling when they stopped motorists in Oakland, California, RAND researchers studied efforts to address this question in other jurisdictions and contexts and found each methodology used to be statistically problematic. The Oakland Police Department integrated RAND into a racial profiling task force that included the American Civil Liberties Union (ACLU), the National Association for the Advancement of Colored People (NAACP), police unions, and others. RAND helped refine data collection methods to ensure that (a) the project could address the complete range of concerns among task force members and (b) the analysis would produce results that task force members could trust, regardless of what they were. RAND's key analytical insight involved a simple experiment: Compare motorist-stop patterns during twilight hours in the days around the twice-annual changes of the clock. On the days before and after the Daylight Saving Time changes, for any given time segment around twilight, driving patterns, traffic volumes, and other factors stay constant and the only day-to-day difference is the officer's ability to see the race of the motorist before the stop. If officers were using race as a factor in stopping motorists, this would be evident in the proportions of blacks and whites among vehicle stops around the beginning and end of Daylight Saving Time. When this experiment revealed no racial profiling in traffic stops, it was not only the police unions but also the NAACP and ACLU that trusted the result. RAND further developed the field of racial profiling analysis with work in Cincinnati and New York City.